DFF: Making a Segment Required based on Another Segment Value.

 We have the below Requirement for the Expense Report Line DFF. Say there are 3 Segments defined for the DFF. Segment 1 Mapped to Attribute1 Segment 2 Mapped to Attribute 2 Segment 3 Mapped to Attribute 3   Segment 1 has a value set attached which can have the values Yes or No. If a user selects the values as Yes for Segment1 then the Segment 2 & 3 should be made Required. If a user selects the values as No for Segment1 then the Segment3 should be made Required.   Any thought from you all on how to do it in the simplest possible manner(Something in the DFF definition and not .PLL/Form Personlization). Thanks in Advance Mohit Gupta